function GPSMarker() {
  var gpsIcon = new google.maps.MarkerImage(
    'images/gps.png',
    new google.maps.Size(10, 11),
    new google.maps.Point(0, 0),
    new google.maps.Point(4, 5)
  );

  this.speed = 0;
  this.heading = 0;

  google.maps.Marker.apply(this, [ { position: new google.maps.LatLng(0, 0), flat: true, icon: gpsIcon, clickable: false } ]);
}

GPSMarker.prototype = new google.maps.Marker({position:new google.maps.LatLng(0, 0)});
GPSMarker.prototype.constructor = GPSMarker;

GPSMarker.prototype.setSpeedHeading = function(s, h) {
  this.speed = s;
  if (h !== false)
    this.heading = h;
}

GPSMarker.prototype.getSpeed = function() {
  return this.speed;
}

GPSMarker.prototype.getHeading = function() {
  return this.heading;
}
